This invention relates to devices for handling and transporting series of substantially identical objects, and more particularly to a rotary device for sequentially transferring folded cards from a feed station to a discharge station.
The use of automatic manufacturing techniques to reduce product cost is well known. Numerous intermittent "pick and place" devices have been developed for re-positioning and/or re-orienting parts between processing stages. One common need is to continuously re-orient a piece or part in the course of its transfer between two conveyors angularly offset from one another.
A rotary wheel or drum, having a vacuum established at its perimeter, has been found suitable for this purpose. For example, U.S. Pat. No. 3,983,987 to Lynch shows a pair of vacuum wheels 17 and 18, each having radial passageways 24. The negative pressure through the radial openings tends to hold articles A against the wheel perimeter as they are transferred from a chute 15 to a conveyor 14, where a spurt of pressurized air is provided from a chamber 50 to release the article. Upper and lower vacuum control devices 63 and 52, for controlling the degree of vacuum drawn into a rotary system, are shown in U.S. Pat. No. 4,136,767 to Sarovich granted Jan. 30, 1979.
The vacuum in a rotary drum or wheel can be drawn only through selected ones of a series of radial suction ports, by use of an arcuate groove formed in a stationary valve plate next to the rotating drum or wheel. Examples of this approach are shown in U.S. Pat. No. 3,921,791 to Bornfleth et al granted Nov. 25, 1975, and U.S. Pat. No. 3,837,378 to Kanki et al granted Sept. 24, 1974. While these patents disclose apparatus appropriate for certain specific applications, they fall short of the need for a simple, inexpensive rotary transfer device that is adjustable and therefore usable in a variety of situations.
Therefore, it is an object of the present invention to provide a high speed rotary transfer device suitable for transporting a variety of objects.
Another object of the invention is to provide a valve plate for use with a rotary transfer device that is adjustable to alter the timing of positive and/or negative pressure applied through the rotary transfer device.
Yet another object of the invention is to provide a simple, cost-effective means for modifying a rotary transfer device to meet a variety of applications.